How to work around this 'Find my iPhone' problem?

I lost my iPhone on the weekend and have it set on 'Lost Mode' with 'Find My iPhone'. Low and behold I just got a notification from my mum's phone saying my iPhone has been found. It's just a notification on the phone, like when you don't have enough room for music when updating it on a computer. As soon as I swiped it, it just led me to the home screen with no other info at all. I log into iCloud and Find My Phone, and it says my lost phone is still offline and there's no new info.
What was with that random notification?! Any help would be great, thank you.

The notification shows that whoever has your iPhone turned it on for long enough for Find My iPhone to locate it's approximate location but what's happened since means the phone has been made untraceable by turning it off or even by destroying it as "hot" phones are a liability to thieves.

As this suggests someone has found your phonon but failed to hand it in, it makes that person a thief. I suggest that you now report a theft to police; in many countries now police can ask for your permission to log into your Find My iPhone app so that they also can track the location and hopefully recover your property and arrest the thief.

They turned it on, realized its icloud locked and shut it off. Now they are running around trying to find out how to get around icloud lock, then after wasting a month of their time they will realize they can't get around it.

You can also put a permanent msg on the screen something like "stolen, email me at xxxxx".